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Joined: Sep 2011
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Looks like it has become a standard, but I have actually no clue. I prefer to work with old phones; max 48V DC + 90V 25HZ dsk Its ok. I want to say thank you over and over, at this point you have given me mountains of information! I am still learning all of it! So, considering the transformers, am I correct 3 types of IT supplies existed in Norway? 230 IT 400 IT 690 IT And 400 and 690 in buildings was stepped down to 230 with building owned transformers? Here is the USA larger buildings are fed with 277/480Y TN-C-S supply from power provider. 277 for lighting and 480 for motor. 480 is then stepped down to 120/208Y TN-S in the building for electrical sockets.
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Joined: Sep 2011
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Just to add, I think a wye primary is a poor choice. If the impact protection shorted to ground, and a phase was also faulted to ground on the LV, this would create a neutral shift in the vector. The other phases would go over 230 volts damaging what ever is connected to them. Just some friendly advice for Norwegian utilities... I mean no harm
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Joined: Jun 2014
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690 are not a used standard here, but more a special ting. 230V IT ,TT , TNC-S are used. 400V are usually TNC-S not IT. Private transformers are usually small for single units using e.g. 400V when 230 are supplied or vica verca. Atotransformers are banned.
Trams/subways runs on 750V DC Train on approx 16-20kV 16-2/3Hz
dsk
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400/690 is occasionally used for large industrial motors and generators in Europe I think.
I'd forgotten that Norway used the same railway power system as Germany, Austria, Switzerland and Sweden.
Denmark is DC, right?
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Don't sweat it You may not have all the knowledge in the world in this area, but so far this thread has become a gold mine of information I never imagined. DSK, let me say thank you over a hundred plus times! You have contributed so much to this thread and answered all my questions hundreds of times over with detail. I have learned a lot. Great stuff. I think you are proof that Scandinavian nations are the nicest and happiest place on earth. Now I know why Norway has so little crime, as its impossible to feel left out of anything. Everyone is so helpful. Thank you for your time! Many thanks from the USA!
Last edited by Meadow; 02/21/15 02:21 PM.
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Joined: Dec 2001
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Yes it does, thanks a lot! Apparently Denmark is an island between Germany and Sweden using 25 kV/50 Hz, the modern European railway standard. The early adopters of electrical railways chose either DC or low-frequency AC because such motors can be controlled simply with series resistors. Before the days of solid state inverters controlling the speed of a 50 Hz AC motor was incredibly complex and required chunky machinery on each loco/EMU. The Hungarians went through all that trouble when they electrified their railways in the 1930s because it was still cheaper than dedicated railway power plants or huge rotary converter stations as we still have in Austria (Germany and Switzerland are moving over to solid state inverters). Seems like Denmark chose the Hungarian way. Edit: low-frequency AC had one huge advantage, it could be transformed on board of the train. Motors at that time couldn't run on more than about 1000-1500 V so DC systems could only go up to 3 kV with series-wired motors but AC systems could easily have 15 kV overhead wire voltage and transform it down to something manageable. The high voltage greatly reduces current and voltage drop, that's why some countries have a mix of power systems, DC on older lines and AC on newer high-speed lines. Apparently the Dutch can't run electric freight trains because of the limits of their 1.5 kV DC overhead supply! The Czech Republic is split, the North is DC and the South is 50 Hz AC.
Last edited by Texas_Ranger; 02/21/15 02:52 PM.
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Joined: Jun 2014
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It's interesting, and I'm learning a lot too. I have designed,(and partly built) units for export to USA, Australia, and other countries. Only the US marked has been a challenge because of their own standards so different from Europe.... or actually not when you learn it to know. Most US 480V machinery will run at 400V 50 hz and visa versa. 20% more power out in the 480V system, but it works, and no smell of burned equipment :-)
dsk
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Joined: Jun 2014
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